Showing papers by "Romano Fantacci published in 2003"
TL;DR: In this article, a fair comparison between direct sequence code division multiple access (DS-CDMA) and orthogonal frequency division multiplexing (OFDM) systems for broadband downstream power-line communications (PLCs) is provided.
Abstract: This paper provides a fair comparison between direct sequence code division multiple access (DS-CDMA) and orthogonal frequency division multiplexing (OFDM) systems for broadband downstream power-line communications (PLCs). The considered schemes seem particularly suitable for high bit rate broadcast flexible communications on low voltage grid in order to guarantee local access. The performance of the considered systems is expressed in terms of bit error rate (BER), derived by simulations under the assumptions of frequency-selective multipath fading channel and additive colored Gaussian noise according to the in-building networks model, under the same overall working conditions of bandwidth occupation, transmitted power, and global data rate.
63 citations
01 Jan 2003
48 citations
TL;DR: The network, derived via a nonobvious modification of the circuit for nonlinear programming introduced by Kennedy and Chua, is shown to be globally asymptotically stable, and as such is able to compute the global optimal solution in real time, without the risk of spurious responses.
Abstract: This brief proposes a neural network for the solution in real time of a class of quadratic optimization problems with equality and inequality constraints arising in code-division multiple access (CDMA) communication systems. The network, which is derived via a nonobvious modification of the circuit for nonlinear programming introduced by Kennedy and Chua, is shown to be globally asymptotically stable, and as such is able to compute the global optimal solution in real time, without the risk of spurious responses. Computer simulations are presented to verify the neural network optimization capabilities and speed, and the performance in the application to CDMA communication systems.
20 citations
TL;DR: The satellite network architecture presented in this paper is designed to provide a complete QoS support for IP traffic based on the DS paradigm, while minimizing the waste of the valuable satellite resource.
Abstract: IP satellite networks are gaining a considerable interest mainly due to their ability to deliver high bandwidth services to nation-wide areas. However some difficulties still exist to implement IP-based transport mechanisms on geostationary satellite networks (i.e. TCP-based protocols are affected by the large delay-bandwidth product). The satellite network architecture presented in this paper is designed to provide a complete QoS support for IP traffic based on the DS paradigm, while minimizing the waste of the valuable satellite resource. The proposed technique operates on two time scales: a short-term reaction compensates fast traffic variations by an appropriate scheduling while a medium term resource allocation mechanism reduces the wasted bandwidth. Copyright © 2003 John Wiley & Sons, Ltd.
16 citations
TL;DR: A new neural network approach, based on the Hopfield model, is proposed in order to reduce the convergence time in different application environments and highlights a fast convergence behavior of the proposed scheme under multipath-fading conditions.
Abstract: The Universal Mobile Telecommunications System (UMTS) which is based on Wideband-Code Division Multiple Access (W-CDMA) techniques is one of the most important broadband wireless communication systems. Adaptive Blind Multiuser Detection was widely considered for mobile receivers. The main drawback of this approach is that it achieves the optimum solution after a certain number of bit times. This paper deals with a new neural network approach in order to reduce the convergence time in different application environments. In particular, a modified Kennedy-Chua neural network, based on the Hopfield model is proposed. The neural network stability was investigated by means of a suitable analytical approach, while the performance of the proposed receiver scheme was derived by means of computer simulations. The numerical results shown in this paper highlight a fast convergence behavior of the proposed scheme, in particular under multipath-fading conditions.
12 citations
20 Mar 2003
TL;DR: This paper presents a turbo multiuser detector for turbo-coded DS-CDMA systems, based on the utilization of a PIC and a bank of turbo decoders, in which the PIC performs interference cancellation after each constituent decoder of the turbo decoding scheme.
Abstract: This paper presents a turbo multiuser detector for turbo-coded DS-CDMA systems, based on the utilization of a PIC and a bank of turbo decoders, in which the PIC performs interference cancellation after each constituent decoder of the turbo decoding scheme. Moreover, we propose a new enhanced estimator of the signal-to-noise-plus-interference-ratio used in the decision device and in the MAP decoding algorithm. By means of computer simulations, we show that the proposed receiver outperforms other similar schemes for medium to very high system loads, in AWGN and multipath fading channel.
8 citations
11 May 2003
TL;DR: An advanced AC scheme proposal that estimates the requesting connections signal to noise plus interference ratio (SINR) by means of accurate multiple access interference (MAI) analysis results and verifies the possibility of a new call admission by valuating if an overall power configuration there exists, whose predicted SINR values satisfy each QoS constraints.
Abstract: Next generation wireless systems, as Universal Mobile Telecommunications System (UMTS), aim at revolutionizing the actual wireless communication paradigm offering real time multimedia services now available on fixed terminals whose quality of service (QoS) requirements could be satisfied by network resources adaptation to traffic conditions. Since radio interface is based on CDMA technology, this system suffers form mutual interference among active connections. Approximately, the communication quality decreases at the increasing of active users number. As a consequence, there exists an active user threshold below which an intolerable QoS degradation is produces, especially for those applications named in 3GPP standard as interactive or background. Therefore, proper admission control (AC) algorithm that mitigates mutual interference by keeping active users under a dynamic threshold, is a crucial topic in UMTS system optimization. This paper deals with an advanced AC scheme proposal that estimates the requesting connections signal to noise plus interference ratio (SINR) by means of accurate multiple access interference (MAI) analysis results. Basically, this algorithm verifies the possibility of a new call admission by valuating if an overall power configuration there exists, whose predicted SINR values satisfy each QoS constraints. Whenever a new connection is accepted, a further optimization is performed in order to allow a QoS higher than the requested value under a maximum radiated power constraint. This value is delivered to power control (PC) algorithm jointly with the associated SINR value. Numerical simulations, closely related to an UMTS system, underline a remarkable number of active users increase up to four times traditional AC policies, together with the maximization of QoS requirements.
8 citations
TL;DR: A new scheduling technique to be adopted at the MAClevel in wireless access systems, named Dynamic Scheduling-Time DivisionDuplexing (DS-TDD), that efficiently manages video, voice, Web and background traffics is proposed.
Abstract: Future generation wireless multimedia communications will require efficient Medium Access Control (MAC) protocols able to guarantee suitable Quality of Service (QoS) levels for different traffic classes while achieving a high utilization of radio resources. This paper proposes a new scheduling technique to be adopted at the MAC level in wireless access systems, named Dynamic Scheduling-Time Division Duplexing (DS-TDD), that efficiently manages video, voice, Web and background traffics. A theoretical approach is proposed in this paper to evaluate the DS-TDD performance with voice and Web traffics. Simulation results have permitted to highlight the following promising characteristics of the DS-TDD scheme: (i) a high capacity of real-time traffics is attained with a QoS insensitive to Web and background traffic loads; (ii) a high throughput can be guaranteed while preserving the QoS levels of the different traffic classes; (iii) heavier downlink traffic loads do not modify the QoS of uplink traffics. Finally, extensive comparisons with different scheduling schemes proposed in the literature have permitted to highlight the better performance of DS-TDD.
7 citations
TL;DR: Different spread spectrum systems are proposed for broadband downstream power-line communications (PLCs) and the performance of the systems considered is expressed in terms of bit error rate (BER), derived by simulations under the assumptions of frequency-selective multipath fading channel and additive coloured gaussian noise.
Abstract: In this paper different spread spectrum systems are proposed for broadband downstream power-line communications (PLCs). Orthogonal frequency division multiplexing (OFDM) technique permits to greatly enhance the system throughput but can be strongly damaged by ‘hidden nodes’ situations. The introduction of suitable hybrid schemes, such as MT-CDMA, allows to efficiently face this inconvenience by increasing system robustness.
The performance of the systems considered is expressed in terms of bit error rate (BER), derived by simulations under the assumptions of frequency-selective multipath fading channel and additive coloured gaussian noise according to the in-building networks model, under the same overall working conditions of bandwidth occupation, transmitted power and global data rate. Copyright © 2003 John Wiley & Sons, Ltd.
6 citations
01 Dec 2003
TL;DR: Simulations show that the Post-combining scheme gives the best results, but it implies more complexity to the mobile terminal, whereas both the proposed ST-MMSE schemes yield significantly better performance than the standard STTD receiver or the conventional RAKE receiver.
Abstract: This paper deals with the comparison among two schemes of space-time MMSE reception implemented for the forward link of a WCDMA multisatellite UMTS environment The so called space-time transmit diversity technique (STTD) has been coupled with the minimum mean square error (MMSE) interference suppression technique. The idea has come from the realization that the diversity gain is limited by a medium-high level of multiple access interference (L. Mucchi et al., 2002). The proposed schemes can be distinguished by the order in which the space-time processing and the MMSE interference suppression are performed. We named ST-MMSE Pre STTD Combining if the MMSE filtering is performed before the space-time combining and ST-MMSE Post STTD Combining if the interference suppression and the space-time combining are jointly processed. A realistic multisatellite UMTS environment has been simulated in order to compare the proposed detectors. Bit error rates have been calculated by mean of Monte Carlo simulations assuming a time-varying satellite channel model. Simulations show that the Post-combining scheme gives the best results, but it implies more complexity to the mobile terminal. Anyway, both the proposed ST-MMSE schemes yield significantly better performance than the standard STTD receiver or the conventional RAKE receiver.
6 citations
01 Jul 2003
TL;DR: An in-depth analysis of the random-access phase has been carried out, thus identifying the conditions that allow a good CD-PRMA-HS behavior and a performance analysis has been developed in order to evaluate the quality of service parameters for both voice and Web-traffic sources.
Abstract: The paper deals with low Earth orbit mobile satellite systems (LEO-MSSs) belonging to third-generation mobile networks and proposes a novel packet-access scheme suitable for a hybrid time-code wideband air interface This medium-access control (MAC) protocol is a modification of the packet-reservation multiple-access scheme with hindering states (PRMA-HS) and is called code-division PRMA-HS (CD-PRMA-HS) Each mobile terminal that needs to transmit makes random accesses on available time-code resources until it receives a positive acknowledgment from the satellite Both real-time voice and Web-traffic sources have been considered in our LEO-MSS scenario An in-depth analysis of the random-access phase has been carried out, thus identifying the conditions that allow a good CD-PRMA-HS behavior Finally, a performance analysis has been developed in order to evaluate the quality of service parameters for both voice and Web-traffic sources
01 Jan 2003
TL;DR: An innovative admission control (AC) policy for CDMA wireless networks, based on minimizing the multiple-access-interference (MAI), is introduced, rendering this approach a proper candidate for variable network traffic management.
Abstract: In this paper, an innovative admission control (AC) policy for CDMA wireless networks, based on minimizing the multiple-access-interference (MAI), is introduced. According to our proposal, an incoming connection is accepted whenever the QoS constraints, for all communications, are respected, that is, the signal-to-interference-plus-noise-ratio (SINR) is kept under control. This parameter mainly depends on traffic load variations. Thus, the MAI arising from a new connection must be considered. This problem can be proactively faced by characterizing MAI and correctly estimating its value. Furthermore, two approaches are presented, named, respectively, static soft AC and dynamic soft AC; the latter involving a dynamic power management. Analytical models describing the first approach are investigated and validated by means of simulations performed on a typical uplink UMTS environment. Moreover, a remarkable gain of the second approach, in terms of dropping probability, is highlighted without, thus rendering our approach a proper candidate for variable network traffic management.
01 Dec 2003
TL;DR: The proposed channel estimation methods, based on a classical mean and a newly adaptive mean square error (AMSE) algorithm, introduce low performance loss, in terms of P/sub e/ and throughput, with respect to the ideal channel estimate situation.
Abstract: In this paper, the performance of a multiuser detection (MUD) receiver is investigated for a multi-carrier-code division multiple access (MC-CDMA) system in an indoor environment. Furthermore, low complexity pilot-aided methods are introduced for estimating channel parameters in an effort to study the resistance of the proposed solution to imperfect channel estimates. Simulation results show that benefits of MC-CDMA schemes, in terms of capacity and probability of error (P/sub e/), are enhanced by means of a selective parallel interference cancellation (S-PIC) receiver (at the expense of moderate increases in overall system complexity). The proposed channel estimation methods, based on a classical mean and a newly adaptive mean square error (AMSE) algorithm, introduce low performance loss, in terms of P/sub e/ and throughput, with respect to the ideal channel estimate situation. Moreover, the AMSE shows better accuracy and faster convergence than the mean algorithm.
01 Dec 2003
TL;DR: A WDCM implementation for a micro cell case is presented, with particular attention to the cluster position and the mobility model concept, and proposed channel model can be used in a link level simulator (LLS).
Abstract: This paper deals with the implementation and the assessment of a wideband directional channel model (WDCM) based on the COST 259 recommendations. Cluster of replicas are introduced by means of tapped delay line (TDL). A good compromise between accuracy of the model and complexity required by the simulator is guaranteed by a suitable statistical approach based on deterministic considerations. In the paper a WDCM implementation for a micro cell case is presented, with particular attention to the cluster position and the mobility model concept. Finally, channel model assessment is performed by comparing simulation results in the general street los radio environment with a recent measurement campaign. Proposed channel model can be used in a link level simulator (LLS).
01 Jan 2003
TL;DR: Two new schemes of space-time MMSE reception implemented for the forward link of a WCDMA multisatellite UMTS environment and the comparison with other two similar space- time MMSE receiver already presented in the literature are dealt with.
Abstract: This paper deals with the introduction of two new schemes of space-time MMSE reception implemented for the forward link of a WCDMA multisatellite UMTS environment and the comparison with other two similar space-time MMSE receiver already presented in the literature. In all this works the so called space-time transmit diversity technique (STTD) has been coupled with the minimum mean square error (MMSE) interference suppression technique. The idea has come from the realization that the diversity gain is limited by a medium-high level of multiple access interference (L. Mucchi et al., 2002, R. Tesi et al., 2001). The proposed schemes can be distinguished by the order in which the space-time processing and the MMSE interference suppression are performed. We named ST-MMSE pre STTD combining if the MMSE filtering is performed before the space-time combining and ST-MMSE post STTD combining if the interference suppression and the space-time combining are jointly processed. A realistic multisatellite UMTS environment has been simulated in order to compare the proposed detectors. Bit error rates have been calculated by mean of Monte Carlo simulations assuming a time-varying satellite channel model. Simulations show that the post-combining scheme gives the best results, but it implies more complexity to the mobile terminal. Anyway, both the proposed ST-MMSE schemes yield significantly better performance than the standard STTD receiver or the conventional RAKE receiver.
TL;DR: A cyclic assignment scheme with a novel traffic policer based on fuzzy logic for video sources and on a token-bucket scheme for Web sources is used and the technique is named Fuzzy Logic-Based Multiple Access (FLBMA) to remark the central function of the fuzzy policer.
TL;DR: It is shown that this receiver, defined as a space-time selective parallel interference-cancellation detector, exhibits good behavior and lowers the computational complexity in comparison with previously proposed alternatives.
Abstract: The paper deals with a multiuser cancellation-detection scheme combined with an antenna array for wideband code-division multiple-access (WCDMA) communication systems in which different traffic loads and data rates are considered. This receiver, defined as a space-time selective parallel interference-cancellation detector, should be used at the base station of a WCDMA communication system. Asynchronous users and multipath fading phenomena are considered. The receiver basic assumption is to divide signals into two different groups according to the received power level. The reliable signals are directly detected and cancelled from the whole received signal at each sensor before making the decision about unreliable signals without any further processing delay. Performance evaluations have been carried out in terms of P/sub e/ (bit error probability) by means of computer simulations. In particular, it is shown that our receiver exhibits good behavior and lowers the computational complexity in comparison with previously proposed alternatives.
01 Dec 2003
TL;DR: The paper considers the design of the modified 'soft' Complementary Code Keying (CCK) modulation/demodulation scheme more suitable for the iterative interference cancellation receiver and shows the performance evaluation of this T-BLAST and SOFT CCK MODEM in the specific environment of the IEEE 802.11b standard.
Abstract: Recent research addresses towards multitransmit, multireceive antenna scheme to improve the performance in high data rate wireless communications. In this paper, we examine the combination of Bell-Labs layered space time (BLAST) wireless architecture and the iterative demapping and decoding, the turbo decoding principle. This structure, known as T-BLAST, was evaluated according to the IEEE 802.11b standard requirements for wireless LAN. The paper considers the design of the modified 'soft' Complementary Code Keying (CCK) modulation/demodulation scheme more suitable for the iterative interference cancellation receiver and shows the performance evaluation of this T-BLAST and SOFT CCK MODEM in the specific environment of the IEEE 802.11b standard. The paper also presents the throughput versus distance to receiver varying the number of transmit antennas in the indoor environment.
20 Mar 2003
TL;DR: By means of analytical derivations and simulations on UMTS environment, a noticeable bit error rate and frame error rate improvements have been shown and a significant link throughput increase is pointed out with a consequent reduced packet delivery delay and power wasting.
Abstract: This paper deals with the application of hybrid automatic repeat request (H-ARQ) techniques to reliable data communications in wireless 3G networks. Basically, retransmission of coded data is endowed with soft combining schemes applied, respectively, to packet replicas, or to decoding algorithm outputs. By means of analytical derivations and simulations on UMTS environment, a noticeable bit error rate (BER) and, then, frame error rate (FER) improvements have been shown. A significant link throughput increase is also pointed out with a consequent reduced packet delivery delay and power wasting.
20 Mar 2003
TL;DR: An advanced admission control scheme that estimates the requesting connections signal-to-noise plus interference ratio (SINR) by means of accurate multiple access interference (MAI) analysis results and verifies the possibility of a new call admission by valuating if a power configuration exists, whose predicted SINR values satisfy each QoS constraints.
Abstract: This paper deals with an advanced admission control (AC) scheme that estimates the requesting connections signal-to-noise plus interference ratio (SINR) by means of accurate multiple access interference (MAI) analysis results. This algorithm verifies the possibility of a new call admission by valuating if a power configuration exists, whose predicted SINR values satisfy each QoS constraints. Numerical simulations, closely related to the UMTS system, underline a remarkable number of active users increase up to four times traditional AC policies, together with the maximisation of QoS requirements.
11 May 2003
TL;DR: Two kinds of H-ARQ techniques, belonging to soft recombining schemes, are proposed and applied, respectively, to consecutive received packet replicas, or to decoding algorithm outputs, without remarkable hardware complexity increase, and can assure a lower packet delivery delay if compared with protocols commonly used in wired networks.
Abstract: This paper deals with the application of hybrid automatic repeat request (H-ARQ) techniques to reliable data communications in wireless 3G networks, whose typical applications have to match accurate quality of service (QoS) requirements. A common approach to guarantee such services enhances the H-ARQ features by exploiting turbo codes error correction capabilities. This paper, following the previous approach, investigates the further benefits achievable by developing a strategy that establishes a connection between packet retransmissions and decoding results. Two kinds of these techniques, belonging to soft recombining schemes, are proposed and applied, respectively, to consecutive received packet replicas, or to decoding algorithm outputs, in both cases, without remarkable hardware complexity increase. By means of analytical derivations and simulations, focused on a typical universal mobile telecommunication system (UMTS) environment, a noticeable bit error rate (BER) and, then, frame error rate (FER) improvements have been shown. For the proposed schemes, whenever communications suffer from low signal to noise ratio (SNR) values, significant link throughput increase is also pointed out. As a consequence, these techniques can assure a lower packet delivery delay, besides avoiding transmitted power wasting, if compared with protocols commonly used in wired networks.
01 Jan 2003
TL;DR: This paper proposes a multiple access scheme for a WLAN supporting real-time (voice) and best-effort ( data) services, which exploits the presence of a broadband multiuser wireless access scheme such as orthogonal frequency division multiplexing (OFDM).
Abstract: Wireless local area networks (WLANs) are one of the most promising access technologies for the upcoming fourth-generation wireless communication systems. In the last few years, several research efforts have been devoted to investigate possible multiple access schemes capable of supporting real-time traffic as well as best-effort data transmissions. In particular, the use of suitable transmission schemes allows not only to achieve higher data-rates, but also to optimize the allocation of traffic in the radio resources depending on the service requirements. In this paper we propose a multiple access scheme for a WLAN supporting real-time (voice) and best-effort (data) services, which exploits the presence of a broadband multiuser wireless access scheme such as orthogonal frequency division multiplexing (OFDM). OFDM allows dividing the radio bandwidth into several sub-bands, thus permitting a flexible resource allocation strategy to be deployed, while satisfying quality of service (QoS) requirements. A high overall network capacity in terms of simultaneously active users is achieved by effectively exploiting the multiuser capabilities offered by OFDM, together with a good service differentiation. A suitable theoretical analysis for the considered protocol has been carried out by applying the equilibrium point analysis (EPA) method, and computer simulation results have been compared with analytical predictions.
TL;DR: The results shown herein permits to evaluate the influence of the channel propagation conditions on the system performance and highlight that the reservation TDMA protocol exhibits a good behaviour for the communication channel under consideration and in comparison with a recent protocol based on the classical PRMA scheme.
Abstract: In this paper, the capability is investigated of a reservation TDMA-based protocol to support constant bit rate and best-effort traffics in Low Earth Orbit (LEO) satellite communication systems under typical propagation conditions. Differently from several previous papers on the same subject, we focus here on a communication channel affected by multipath fading and characterized by a high round trip delay. In our protocol, a higher priority is given to constant bit rate terminals with respect to best-effort data terminals. The performance for constant bit rate and best-effort terminals was derived by means of a suitable analytical approach and computer simulations. The results shown herein permits to evaluate the influence of the channel propagation conditions on the system performance. Moreover, they highlight that the reservation TDMA protocol exhibits a good behaviour for the communication channel under consideration and in comparison with a recent protocol based on the classical PRMA scheme. Copyright © 2003 John Wiley & Sons, Ltd.
TL;DR: This paper proposes a low complexity joint space-time multiuser detection algorithm for asynchronous DS/CDMA antenna array systems that is shown to be near-far resistant, even in worst fading cases, and to exploit completely array introduction while maintaining acceptable computational complexity.
Abstract: This paper proposes a low complexity joint space-time multiuser detection algorithm for asynchronous DS/CDMA antenna array systems The proposed multiuser detector is composed of an adaptive antenna array, used as a linear beamformer, and a sliding window decorrelator A QPSK modulation scheme is used in order to increase bandwidth efficiency Numerical results are given in terms of Bit Error Rate (BER) under the assumption of a frequency-selective Rayleigh slow fading channel In particular, the proposed receiver is shown to be near-far resistant, even in worst fading cases, and to exploit completely array introduction while maintaining acceptable computational complexity The proposed architecture avoids linear filter realization of the decorrelator, which is impractical in the case of a large number of users, and operates with relatively short data frames instead of the complete information sequence Finally, this receiver is very flexible to changes in timing configuration
01 Jan 2003
TL;DR: For reducing computational complexity, a cellular neural network (CNN) has been proposed for the on-board switching problem; several traffic classes have been considered and switching algorithm has been implemented within a CNN taking into account their priority, queue length and time spent inside queues.
Abstract: Quality of Service (QoS) has become an important topic in modern telecommunication network in order to guarantee multimedia traffic. In IP networks, diffServ seems to be the best approach to satisfy QoS constraints, due to its end-to-end philosophy. Actual trend is to consider satellite on-board switching capabilities for managing multibeam input and output. In this paper, for reducing computational complexity, a cellular neural network (CNN) has been proposed for the on-board switching problem; several traffic classes have been considered and switching algorithm has been implemented within a CNN taking into account their priority, queue length and time spent inside queues. Numerical results shows performance similar to optimal switching solution, but with a higher flexibility due to neural techniques. Simulation results have been driven with memoryless distribution and heavy-tailed distribution for several input buffer size and switch dimension.
01 Jan 2003
TL;DR: The proposed receiver is based on the utilization of a PIC and a bank of turbo decoders and a new enhanced estimator of the signal-to-noise-plus-interference-ratio is used in the decision device and in the MAP decoding algorithm.
Abstract: This paper presents a Turbo Multiuser Detector for Turbo-Coded DS-CDMA wireless communication systems. The receiver is based on the utilization of a PIC and a bank of turbo decoders: particularly, the PIC performs interference cancellation after each decoding iterations of constituent decoder. A new enhanced estimator of the signal-to-noise-plus-interference-ratio is used in the decision device and in the MAP decoding algorithm. By means of computer simulations, we will show that the proposed receiver ouperforms other similar schemes for medium to very high system loads, in AWGN and multipath fading channel.
TL;DR: The proposed receiver, defined as selective partial parallel interference cancellation (SP-PIC), is supposed to be used at the end of an up-link channel characterized by multipath fading phenomena and exhibits an improved bit error rate (BER) and a low computational complexity, linear with the number of users.
Abstract: This paper deals with a cancellation multiuser detector for CDMA communication systems. The proposed receiver, defined as selective partial parallel interference cancellation (SP-PIC), is supposed to be used at the end of an up-link channel characterized by multipath fading phenomena. The SP-PIC main feature is to perform a weighted selective cancellation of the co-channel interfering signals according to the received power level. With respect to other approaches, the proposed detector exhibits an improved bit error rate (BER) and a low computational complexity, linear with the number of users. Copyright © 2003 John Wiley & Sons, Ltd.
11 May 2003
TL;DR: The obtained results between the proposed FMC system and an existing UMTS network and the improvement of performance in terms of bit error rate with proposed receiving system are obtained.
Abstract: This paper deals with the proposal and performance evaluation of a fixed microwave communication (FMC) system that shares the same bandwidth as that of an existing UMTS network. The main application of the FMC system is for wireless connections between remote base stations and a core network access point for an UMTS network implementation in a dense urban environment, where a wired connection could be very expensive for service providers. Besides, sharing of the same frequency band could be attractive for the actual cost and lack of frequency spectrum. The mutual interference effects between the FMC and the existing UMTS systems are investigated by focusing on typical application scenarios. The performance for the two systems under consideration has been evaluated in terms of bit error rate by means of computer simulations for proposed receiving scheme where mutual interference are, firstly, detected and then canceled from the other system. The obtained results between the proposed FMC system and an existing UMTS network and the improvement of performance in terms of bit error rate with proposed receiving system.
TL;DR: In order to highlight the good behavior of the proposed approach, performance comparisons are shown with the ideal case of perfect knowledge of the channel parameter values, as well as with the classical implementation of the considered channel parameter estimation algorithm.
Abstract: The paper deals with the performance evaluation of a pilot-aided channel parameter estimation method suitable for applications in direct-sequence code-division multiple-access (DS-CDMA) communication systems. Differently from previous approaches, a suitable selective interference cancellation algorithm is used in order to reduce multipath interference on the channel parameter estimation and the detection of the information-bearing signals due to pilot signal replicas. Simulation results demonstrate the good channel parameter estimation capability of the proposed method in the case of uplink communications and different types of receiving schemes. In order to highlight the good behavior of the proposed approach, performance comparisons are shown with the ideal case of perfect knowledge of the channel parameter values, as well as with the classical implementation of the considered channel parameter estimation algorithm.